Method and device for sewage treatment

ABSTRACT

The present invention relates to a process for utilizing waste waters which comprises the separate collection of gray water and/or black water and membrane filtration of the separately collected gray water and/or solids/liquid separation of the separately collected black water. The present invention preferably relates to a process for producing potable water from gray water or one or more of its partial streams. Moreover, an apparatus for producing potable water from gray water and an apparatus for utilizing black water and its use is described.

FIELD OF THE INVENTION

The present invention relates to a process for utilizing waste waterswhich comprises the separate collection of gray water and/or black waterand membrane filtration of the separately collected gray water and/orthe solids/liquid separation of the separately collected black water.The present invention preferably relates to a process of producingpotable water from gray water or from one or more of its partialstreams. Moreover, an apparatus for producing potable water from graywater and an apparatus for utilizing black water and its use aredescribed.

SUMMARY OF THE INVENTION

The present method comprises the treatment and recycling of theseparately collected individual waste water streams of gray water andblack water, which is preferably divided into faecal waste water andurinal waste water and can be separately collected, in order to thusprovide a precondition for a highly efficient water management inregions with water problems.

The process is preferably based on the separate routing of black andgray waters and also preferably on the use of water-saving toilets.

The gray water can be used to produce potable water. The individualpartial gray water streams can be pretreated separately and used toproduce potable water. One aspect of the process is the use of sea waterdesalinization plants in the treatment of gray water. The effectsachieved in the desalinization plant are not only a substantial removalof residual substances and simultaneous sanitation, but also a greatreduction of the osmotic pressure.

The basic idea underlying the process is the maximization of the mineralfertilizer concentration by open liquid circulation by collecting thewaste water together with the organic waste fraction in the discharge ofwaste water treatment plants.

The nutrients of the urinal waste water can be separately collected byseparation toilets and urinals and can be anaerobically recovered. Theblack or faecal waste water is oxidized to nitrification and is reusedto flush toilets and urinals, and is thus only used as a transportationmeans, in which the nutrients can be concentrated and discharged.Moreover, nitrate can be used as a flotation aid of the solids in theanaerobic first solids/liquid separation. In the case of composting,there is an additional cycle. This liquid cycle starts with theirrigation of the compost with the effluent from an aerobic waste watertreatment step. The nutrients released by composting are thus washedaway and concentrated in the outlet of the waste water treatment plantby irrigation water supplied to the aerobic treatment step. Suitablemeasures to greatly prevent denitrification can also be taken dependingon the process variant. The theoretically smallest discharge volume ofabout 2 l/(PE*d) and the thus possible drying of the mineralizednutrient enables treatment without difficulties and odorless recyclingof the nutrients into the nutrient cycle.

Bio waste is processed together with any resulting sludges in order toproduce bio gas and compost.

The starting substrates

Definitions

Waste and dirty waters are the sum parameters of all types of individualwaste streams of industrial or domestic origin. The following individualwaste water streams are of particular interest here:

Faecal waste water is defined as waste water which is only laden withfeces (for instance from the feces outlet of urine separation toilets);other waste waters of similar composition stemming from other sourcescan be admixed here.

Urinal waste water is defined as waste water which is only laden withurine and stems from all kinds of urinals and/or from the urine-ladenoutlet of urine separation toilets; in this case, too, other wastewaters of similar composition stemming from other sources can beadmixed.

Black water is defined as waste water laden with both urine and feces,for instance from all kinds of toilets and urinals. Urinal waste waterand/or faecal waste water can be drained and collected in a separatesewerage net. Moreover, the black water and/or its partial streams ofurine waste water and faecal waste water can be received in surges inthe same sewerage nets, and treated separately. In cases of particularsimilarity regarding pollution parameters, other waste waters fromagriculture (for instance liquid pig manure) and/or from other sourcescan be admixed.

Gray water is defined as domestic waste water which is not or hardlyladen with urine and/or feces and/or is defined as other waste water ofsimilar composition stemming from laundries and/or other sources, whichcan be received in one or several separate sewerage nets. According toits origin and/or composition it can be subdivided into several greywater partial streams. The gray water can be composed of all conceivablecombinations of all conceivable numbers of domestic and similar wastewater sources, but must not contain black water (feces and/or urine),although a portion of faecal and/or urinal waste water admixed to one orseveral partial streams of the gray water does not make a difference tothis definition.

Toilet as used herein is the general term for all types of toilets.Toilets with water supply can be divided into flush toilets andwater-saving toilets.

Flush toilets are conventional toilets which are commercially availabletoday and may also be equipped with water-saving devices (for instance awater saving key).

Water-saving toilets are special constructions with a high water savingeffect, such as for instance vacuum toilets, urine separation toilets,etc.

Urinals are all types of separate urine outlets with or without waterflushing, as for instance simple runs, urinals with individual orautomatic water flushing, water-free urinals, etc.

Bio waste is defined as solid, biologically degradable waste productswhich may contain biologically inert components.

Carbon as used herein is defined as referring to all organic carboncompounds (CSB and BSB) which may be contained in black and gray watersand in bio waste. It may also refer to carbonates.

Nitrogen as used herein is defined as referring to all organic andinorganic nitrogen compounds which may be contained in black water andgray water and in bio waste.

Phosphorus as used herein is defined as referring to all organic andinorganic phosphorus compounds which may be contained in black water andgray water and in bio waste.

Filtration covers all coarse screen and/or fine screen filters and/ormembrane (filtration) methods that can be used in waste waterpurification and potable water recovery. It includes all filtrationand/or membrane methods known to the a skilled person, such as ultra ormicrofiltration, which are for instance described in the ATV volumes,Ulmann's Enzyklopädie, and other technical literature and technicaljournals, for instance Korrespondenz Abwasser, etc., and/or available onthe market. Furthermore, process-enhancing additives may be added.

Solids/liquid separation covers all separation processes of liquid andsolid materials which can be used in domestic waste water purificationand potable water recovery, as e.g. sedimentations, and which aresuitable (hydrocyclone classifiers, for example, do not lend themselvesto solids/liquid separation in larger people equivalents connectionsizes). For instance all types of filtration processes including reverseosmosis and/or other membrane processes for solids/liquids separationcan be used. They include all processes for solids/liquid separationknown to a skilled person, such as for instance adsorption processes,precipitation, filtration and membrane processes, dedimentation andflotation processes etc., which are for instance described in the ATVvolumes, Ullman's Enzyklopädie and other technical literature andtechnical journals, e.g. Korrespondenz Abwasser etc, and/or available onthe market. Furthermore, process-enhancing additives may be added.

Fixed bed processes cover all processes in which microorganisms growsessily on a fixed and/or mobile matrix, such as trickling filters, RBC(rotating bio contactor) filters and rotating discs, all types of soilfilters, fluidized bed processes, sand filter, planted soil filters etc.They include all processes that are known to a skilled person, which arefor instance described in the ATV volumes, Ullman's Enzyklopädie andother technical literature and technical journals, e.g. KorrespondenzAbwasser etc, and/or available on the market. Process-enhancing additivemay also be added.

Activated material processes comprise all processes in whichmicroorganisms float freely in the liquid to be treated, such as forinstance activated sludge processes, SBR (sequencing batch reactor)plants etc. They include all microorganism-based oxidation processeswhich are known to a skilled person and are for instance described inthe ATV volumes, Ullman's Enzyklopädie and other technical literatureand technical journals, e.g. Korrespondenz Abwasser etc, and/oravailable on the market. Process-enhancing additive may also be added.

Oxidation by microorganisms, aerobic treatment step and wet oxidationare synonyms within the meaning of the present invention and are thegeneric terms of oxidative fixed bed and activated material processesand other nature-resembling processes. They include all processes thatare known to a skilled person, such as microorganism-based oxidation,which are for instance described in the ATV volumes, Ullman'sEnzyklopädie and other technical literature and technical journals, e.g.Korrespondenz Abwasser etc, and/or available on the market.Process-enhancing additive may also be added.

Removal carbon covers all processes for removing carbon from a liquid.It comprises all processes which are known to a skilled person, such asmicroorganism-based oxidation, e.g. adsorption processes, e.g.precipitation processes and e.g. chemical oxidation processes, etc,which are for instance described in the ATV volumes and other technicalliterature and technical journals, e.g. Korrespondenz Abwasser etc,and/or available on the market.

1.2 Comparison of the domestic waste water partial flows

Most people know little about the dirty water produced by ourcivilization. As a rule, they do not know that it can be composed ofvery different “waste waters”. Within the meaning of this invention theterm “partial stream of waste water” and the term “partial stream” areused as synonyms.

The following Table 1 is a compilation of the approximate distributionof black and gray water components. The columns “black water” and “greywater” show the percentage distribution of the waste water components.

TABLE 1 Profiles of black and grey waters Parameters Black water Graywater amount 20-30% 70-80% carbon 50-60% 40-50% Total nitrogen >99% <1%phosphorus  >99%*  <1%* sulfur >98% <1% microelements >95% <1% path.bacteria >99% <1% * values for the use of phosphate-free detergents

The values indicated in Table 1 are maximum values which may vary inindividual cases. The existing studies are not significant enough. Table1 shows how little sense it makes to mix black water with gray water. Inthe case of lack of nutrients in gray water, or in any combination ofpartial streams of gray water, a part of the oxidized nutrients of theblack water can be added for complete carbon degradation.

Table 2 shows the sources from which the individual loads of materialcome.

TABLE 2 Origin of pollutant loads Parameter carbon total nitrogenphosphorus source g/(E * d) % g/(PE * d) % g(PE * 4) % gray water 1540 >0.2 >1 — — feces 17 46 1.5 11 0.6  43 urine 5 14 12.2 88 0.8  57total 37 100 13.9 100 1.4 100

Table 2 shows the different loads of carbon, nitrogen and phosphorousfrom the sources “gray water”, “feces” and “urine”. The different loadprofile which the feces and urine sources have in respect of the carbonand nitrogen parameters justifies separate collection and/or treatmentof the urinal waste water.

Black water

As mentioned before, waste water from toilets and urinals is termedblack water. It is composed of feces, urine and water. Urine containsmore than 80% of daily produced human nitrogen (urea) dissolved inwater. Feces contain about 50% of the daily produced human carbon insolid form and more than 50% of the phosphorus and 10% of the nitrogen.Almost the whole range of pollutants can be found here: carbon,phosphorus and potassium primarily in the feces, nitrogen mainly in theurine. Moreover, black water contains pathogenic bacteria from the humanintestinal tract (so-called coliform bacteria). The bacteria which arecontained in the sedimented sludge, can be completely killed bysubsequent fermentation and composting, the bacteria contained in thewater must be sterilized to be killed completely.

Regarding quantity, black water amounts to about 30% of the totaldomestic waste water. However, this quantity can be reduced to less than15% by the choice of suitable water-saving toilets. Here, thecalculations should always be checked correctly. The construction costsand operation costs of the process could be dramatically reduced by theseparation of the black water, but it is necessary to install a secondsewerage net. However, since it can be installed in parallel with thesewerage net that must be installed anyway, only the costs for the pipesand minor additional costs for the construction of the conduit net arisein addition.

From a scientific point of view, feces and organic waste consist of thesubstances, life consists of: They primarily consist of carbon (C),oxygen (O), hydrogen (H), nitrogen (N), sulfur (S) and phosphorus (P),but also of a whole range of trace elements, such as for instancepotassium (K). Here, the compositions vary depending on nutrition habitsand/or economic conditions. Primarily carbon, nitrogen and phosphorusare environmentally relevant for water pollution. They are produced inan energy-intensive form and are expensively removed from the water byconventional sewage treatment plants.

Carbon is biologically converted in water into CO₂ by bacteria in thepresence of oxygen. Thus, a great amount of oxygen is used up in thisconversion. One consequence of this is that the fish in the watersuffocate. Plants are able to assimilate and utilize the thus formed CO₂from the air. Hence, carbon is not a fertilizer.

Nitrogen, phosphorus and potassium are factors in short supply in plantgrowth and are thus the main components of fertilizers. Potassium isenvironmentally inert in water, while nitrogen and phosphorus may leadto an explosion-like algae growth in waste water. Algae are also plantsand thus assimilate carbon from the air, and in the presence ofnutrients thus lead to a carbon-enrichment in water, which leads to thedevelopment of catabolic food chains and to a great oxygen depletion ofwater and thus to the death of fish. The term used is the water has“turned” or “eutrophied”.

The nutrients are suitable fertilizers for agricultural use. Commercialmineral fertilizers inter alia consist of saltpeter (KNO₃) and phosphate(PO₄). Exactly these substances are produced by the process and may bereturned in solute or solid form to the production.

Gray water

Gray water is the waste water from all other domestic sources (see thedefinitions above), such as showers, wash-basins, washing machines,kitchen waste water etc. Gray water is practically nitrogen-free andphosphorus-free; hence it can be purified to highest quality withrelatively little expenditure.

Waste water from dish-washers is usually allocated to gray water, butshould be directed to black water because of its composition ofpollutants.

The pollution of gray water compared to that of black water is minor andcan be purified with relatively little expenditure. Gray water containsnitrogen impurities only in very low trace amounts and is considered tobe practically free from phosphate, as predominantly phosphate-freedetergents are used nowadays.

Gray water amounts to about 70 to 80% of the daily waste water producedand accounts for the largest quantity and is particularly suitable forrecycling for the following reasons:

1. it is not contaminated with coliform bacteria

2. it involves no ethical problems for the consumer of potable water

3. it shows a low carbon pollution

4. it shows a minimum nitrogen and phosphorus pollution.

The production of potable water from gray water is particularlyworthwhile for communities in countries where potable water is in shortsupply, as for instance in the Maledive Islands, where 1 m³ of potablewater now costs more than 6 US $.

Bio waste

The amounts of bio waste vary considerably. For instance the amount inGerman communities is only about 200 g per inhabitant and per day, butis more 1.2 kg per day in Asian hotels. Bio waste contains the residualquantities of nitrogen and phosphorus not contained in black water.

Prior art

Control sewage treatment plants and centralized sewerages

Sewage treatment plants which purify waste waters that is to say whichexpensively remove waste water components and direct the purified watervia rivers to the sea represent the state of the art. Hence, this wateris admixed with salt and withdrawn from the fresh water cycle. Inregions where water is in short supply, fresh water is for instanceproduced by sea-water desalinization plants where the process of thepresent invention offers an inexpensive alternative. The prior artcovers a linear flow through technique and essentially suffers from thefollowing drawbacks:

1. The most different types of waste waters from commerce, industry andhouseholds are admixed. Rain water is often also directed to thecombined sewage system. The consequences of this admixture are that

recovery and recycling of the nutrients from black water is impossiblebecause of their admixture with poisonous industrial waste waters;

for the same reason, a poisonous sewage sludge is formed

low-salt waste waters are directed to the sea via the surface watercollectors and thus fresh water is wasted, producing considerable costsespecially in regions where water is in short supply;

the low concentration of the waste water components requires theirtechnically sophisticated and expensive removal;

non-purified waste waters are washed out by rain peaks.

2. Inflexibility of centralized systems. A rigid system cannot reactswiftly to rapid changes in the requirements, as for instance in thebooming touristic areas.

Decentralized separation of black and gray waters

Historically, black water was treated separately especially in Asia. Inthis connection, especially the bio gas plants of India and China andthe “Nightsoil” treatment methods of Japan and Korea are to bementioned. The process variations can be described as follows:

a) Heat treatment process

After coarse particle removal, the black water is passed to aquantitative equalization tank. After heating and subsequentsolids/liquid separation, the black water is diluted with fresh water ina ration of 1:20, and subjected to an activated sludge process.

b) Anaerobic treatment (anaerobic digestion process)

After coarse particle removal and quantitative equalization, the blackwater is subjected to a two-stage anaerobic process and after subsequentsolids/liquid separation is diluted with fresh water in a ratio of 1:20,and directed to an activated sludge process.

c) Aerobic process aerobic digestion process)

After coarse particle removal and quantitative equalization, the blackwater is subjected to aerobic treatment, and after subsequentsolid/liquid separation the black water is diluted with fresh water in aratio of 1:20, and subjected to an activated sludge process.

d) Two-stage activated sludge process

After coarse particle removal and quantitative equalization, the blackwater is diluted with water in a ratio of 1:10 and treated in a firstactivated sludge process. After subsequent solids/liquid separation theblack water is again diluted with fresh water in a ratio of 1:10, andsubjected to a second activated sludge process.

In recent times, the separation of black and gray water has been reducedto practice only in Norway and in the Federal Republic of Germany andonly in a few projects.

e) Gray water processing

In Norderstedt, near Hamburg, black and gray waters were collectedseparately. The gray water is processed in a one-stage procedure, andjust as the untreated black water, is then directed to a combines sewagesystem. The drawbacks of this process concept are the following aspects:

Gray water processing at best allows its reutilization as flush waterfor toilets and urinals.

The introduction of untreated black water makes it impossible to closethe nutrient cycle.

f) Fermentation of black water and bio waste

At present, Lübeck plans a residential area in which black water isseparated from gray water. It envisages fermentation of the total blackwater with bio waste and subsequent use of the fermentation broth inagriculture. The unfavourable C:N ratio is to be counteracted by anincrease of the active bio mass in the anaerobic reactor. The drawbacksof the process in particular in the use in touristic areas with shortwater supplies are the following aspects:

Odorless application of the nutrients in the vicinity or on touristicgrounds (for instance golf courses, parks, public gardens etc.) is notpossible.

With a previous solids/liquid separation step, the volume of the bio gasplant could be reduced to about a fourth while operation stability couldat the same time be increased because of the improved C:N ratio.

Water-saving in the toilet sector is only possible via the use ofwater-saving toilets, given the absence of a black water cycle.

g) Fermentation of black water and bio waste

A pilot plant for the solar residential area “am Schlierberg” workingaccording to the same process as that of Lübeck (see below) was put intooperation in Freiburg in May 1997. During the test phase, acidificationtendencies on account of the too low C:N ratio were reported. Followingthe test results, the process according to FIG. 3 was modified end of1997 by the engineers working on this project. The drawbacks of thisprocess when used in touristic areas suffering from short water suppliesare the same as in the case of the previously discussed process.

h) Aerobic black water oxidation

An aerobic thermophilic oxidation plant for total black water has beenbuilt in Norway near Oslo. The drawbacks of this process are the highenergy consumption of the CSB fraction and the absence of bio gasproduction.

The processes known in the art are, however, inadequate for many wastewater removal or utilization areas. Hence, it is an object of theinvention to provide an improved process for waste water utilization.This object is achieved by the embodiments specified in the claims.

Thus, the invention relates to a process for utilizing waste waters,which comprises the following steps:

(a) separate collection of gray water and/or black water; and

(b) membrane filtration of the gray water separately collected in (a)and/or solids/liquid separation of the black water separately collectedin (a).

In a preferred embodiment of the invention, the process for producingpotable water from gray water or from one or more of its partial streamscomprises the following steps:

(a) separate collection of gray water or one or more of its partialstreams; and

(b) membrane filtration of the gray water separately collected in (a) orone or more of its partial streams.

In a particularly preferred embodiment, membrane filtration is carriedout by reverse osmosis or ultra- or microfiltration.

In another particularly preferred embodiment the ultra- ormicrofiltration is followed by a desalinization step.

In another particularly preferred embodiment, membranes having a poresize of at the most 2 μm are used for ultra- or microfiltration.

In another particularly preferred embodiment, membranes having a poresize of at the most 0.2 μm are used for ultra- or microfiltration.

In another particularly preferred embodiment, one or more mechanical,physical and/or chemical purification steps precede (b).

In another particularly preferred embodiment the process according to(a) comprises the following steps:

(i) solids/liquid separation; and/or

(ii) carbon removal

In another particularly preferred embodiment step (ii) is followed bysolids/liquid separation.

In another particularly preferred embodiment, solids/liquid separationis carried out by flotation, sedimentation, filtration or precipitation.

In another particularly preferred embodiment, carbon removal is carriedout by oxidation with the use of microorganisms.

In another particularly preferred embodiment, the process of inventioncomprises the following step subsequent to (b):

(c) sanitation and/or modification of the water structure of the graywater or one or more of its partial streams recovered in (b).

In another particularly preferred embodiment, sanitation is a treatmentwith chlorine.

In another preferred embodiment of the invention, black waterutilization comprises the following steps:

(a) separate collection of black water from toilets with or withouturinals;

(b) solids/liquid separation of the black water collected in (a);

(c) oxidation by microorganisms of the liquid phase recovered in (b);

(d) solids/liquid separation of the product obtained in (c);

(e) utilization of the liquid phase obtained in (d) (ea) for collectingblack water according to (a); and/or (eb) as a mineral fertilizer; and

(f) optional repetition of steps (a) to (ea) one or more times.

In a particularly preferred embodiment, the black water is separatelycollected in step (a) as faecal and urinal waste waters and the faecalwaste water is treated according to steps (a) to (f).

In another particularly preferred embodiment of the invention, at leasta part of the urinal waste water is added to the faecal waste waterbefore step (c).

In another particularly preferred embodiment of the invention, thesolids/liquid separation in (b) is a flotation process in the event thatsteps (a) to (ea) are repeated one or more times.

In other particularly preferred embodiments of the invention, one ormore mechanical, physical and/or chemical purification steps precedestep (c).

In another particularly preferred embodiment of the invention, thesolids/liquid separation in (d) is a filtration process.

In another particularly preferred embodiment, the solids/liquidseparation in (b) is a sedimentation or filtration process.

In another particularly preferred embodiment, the product from (d) isintermediately stored in a storage tank and in the case of a higherperformance demand, is supplied again to the oxidation equipment underincreased air supply.

In another particularly preferred embodiment, the oxidized black waterand/or faecal waste water is subjected to sanitation prior toreutilization and/or to a modification of the water structure.

In another particularly preferred embodiment, the solids are removedfrom the urinal waste water by filtration.

In another preferred embodiment, the solids from the gray water and/orthe black water and/or faecal waste water are subjected to a one ortwo-step anaerobic fermentation process together with or withoutfragmented bio waste.

In another particularly preferred embodiment, the potable water isfilled into containers.

In another particularly preferred embodiment, the mineral fertilizerand/or compost is filled into containers.

Moreover, the invention relates to an apparatus for carrying out theprocess of the invention which comprises a reactor in which steps (b),(c) and (d) are carried out.

The apparatus according to the invention comprises membranes asexplained above, as well as a mixer, an aerator, a scum offtake, andoptionally other components.

In another particularly preferred embodiment, the apparatus comprises aseparator in which the process steps characterized in the process of theinvention are carried out.

Furthermore, the invention relates to the use of the apparatus of theinvention for utilizing black water.

In another embodiment, the invention relates to the use of the apparatusof the invention in order to produce potable water from gray water.

THE FIGURES SHOW THE FOLLOWING

FIG. 1 shows the black water module and bio waste module. It depicts theblack water cycle with or without urinal waste water. In addition, itshows the interaction with the bio waste treatment, the treatment of biowaste being a preferred embodiment of the process of the invention.

FIG. 2 shows the gray water module and its recycling for re-use. Thanksto the division of the gray water into three separate partial wastewater streams, a voluminous preliminary sedimentation of the gray watercan be prevented. The treatment of the gray water and one or more of itspartial streams in a desalinization plant is an important process step.The desalinization plant can be used in the present process in amultifunctional way because of the low osmotic pressure. Process step 2d shows the optimum interaction with the bio waste module.

FIG. 3 shows the cycle of the nutrients between collection andutilization. It, in particular, shows the cycle of compost water andachievable nutrient concentration.

FIG. 4 shows an example of a possible compact design of the black watermodule apparatus of the invention. It, in particular, shows an activatedsludge tank which allows the total module to adapt flexibly to the dayprofile of amounts and loads produced in a hotel or residential areaetc.

FIG. 5 shows an example of the black water cycle in the embodiment ofthis compact black water module.

THE EXAMPLES ILLUSTRATE THE INVENTION

The process according to the invention is explained in more detail onthe basis of FIGS. 1 and 2.

Optimum use of the new process herein proposed, requires the existenceof a separate black and gray water discharge system. For instance in thecase of hotel blocks, this discharge system to be newly installed inaddition of the existing one should be easy to realize in the utilitylines in the course of a renovation or new construction, while the hotelcontinues to operate, if the works are properly scheduled.

Sewerage nets and sewage treatment plants do not exist in all Europeantouristic areas and those which exist are all completely overloaded bythe steadily increasing tourism.

In recent times, infrastructures are developed in Southern Europe, whichare similar to those built in other countries (for instance in Germany)in the fifties and sixties. Central sewerage nets are installed andcentral sewage treatment plants are newly built or improved.

However, such central solutions many times and in particular intouristic areas with high touristic growth rates are no permanentsolutions, as central systems and plants cannot grow as rapidly astourism. Hence, decentralized solutions, which permit flexible adaptionof the capacity to the needs should on principle be sought.

The process herein proposed is so flexible that it can be implementedinto an existing infrastructure at low costs. For instance existingcentral structures can be continued to be used for cost reasons and canbe supplemented by the decentralized system in parallel to the centralsystem.

EXAMPLE 1 The possibility of implementing the process in aninfrastructure possessing a central sewage treatment plant and seweragenet

A community possesses a central sewerage net, which is in reasonableconditions, and an (overloaded) central sewage treatment plant. In thiscase, the existing sewerage net can be used for collection and thesewage treatment plant can be used for processing the gray water. Theblack water from toilets and urinals is detached from the central systemand collected in small decentralized systems and processed in blackwater modules and recycled. This does not only provide the possibilityof reutilizing the gray water, but also results in a substantialincrease in the capacity of the existing sewage treatment plant;overload is thus avoided and a good discharge quality ensured.

EXAMPLE 2 Possibility of implementing the process in an infrastructurewithout a central sewage treatment plant and sewerage net

A community does not possess a waste water infrastructure, andconsequently it possesses neither a sewage treatment plant nor asewerage net. In this case, it is possible to use several completeprocess modules (black and gray water modules) in a decentralized manner(for instance in every major hotel or residential block).

Thus, the implementation of the process in local infrastructures shouldalways be decided upon on a case by case basis, as it depends on manylocal factors, such as the infrastructure, price structure of wastewater and potable water, possibly the water and fertilizer requirementsin agriculture etc.

The following Table 3 shows some implementation possibilities indifferent existing infrastructures

TABLE 3 Implementation possibilities in existing infrastructures Potablewater supply situation Existing Extreme water No water Infrastructureshortage Water Shortage shortage No sewage small decentralized blacksmall decentralized black small decentralized treatment plant; no andgray water systems and gray water systems and black and gray watersewerage net and standardized bio standardized bio converter systems;converter modules modules standardized black water modules and plantedsoil filters for gray water Old sewage detachment of black waterdetachment of black water small decentralizad treatment plant; by smalldecentralized by small decentralized black black water systems oldsewerage net black water systems end water systems and with planted soilstandardized black water standardized black water filters; utilizationof modules; utilization and modules; utilization and existinginfrastructure improvement of existing improvement of existing for graywater infrastructure for gray infrustructure for gray water purificationwater optionally direction and optionally percolation or into thedesalinizatian plant irrigation New sewage detachment of black waterdetachment of new an individual cost treatment plant, by smalldecentralized constructions by small benefit analysis new sewerage netblack water systems and decentralized black water needs to be preparedstandardized black water systems and standardizad modules; utilizationand black water modules: improvement of existing utllizatlon of existinginfrastructure for gray intrastructure for mixed water water, optionallydirection purification. Aiming at long- into the desalinizatien plantterm separatian of gray water and black water.

FIG. 1: The black water and bio waste modules

The process and the apparatus should preferably be placed as a compactmodule into the basements of houses accommodating one or more families,and thus no waste water sewerage net whatsoever needs to be installed.

The process is preferably based on the separate discharge of black andgray waters and also preferably on the use of water-saving toilets. Theprocessed waste water and/or preferably black water can be applied togreen areas and/or directed to the ground water after optionalsanitation or disinfection.

The black water and bio waste modules are highly interrelated, andtherefore it would appear expedient to describe them together. Thedashed arrows or boxes in the process in FIG. 1 represent options orprocess variants.

The black water stream

The process is preferably used when the number of toilets exceed 20. Theaim of this partial-stream-process is the production of mineralfertilizer, compost and bio gas from black water. The most essentialcrucial point of the process is the black water cycling between toilets,solids/liquid separation, oxidation (oxidation by means ofmicroorganisms and/or carbon removal) and solids/liquid separation.Hence, the loads of nutrients can be concentrated as desired, with theresult that the volume in which the nutrient loads are dissolved is verysmall. Another characteristic feature of the partial-stream-process isthe solids/liquid separation of black water and the black water cyclefor compost water, all of which is explained in the following list ofprocess steps on the basis of FIG. 1. The numbers in the descriptioncorrespond to those of the correspondingly numbered process steps ofFIG. 1.

Process steps (1) to (6) show the black water cycle with oxidativenutrient production without the use of separation toilets (fat arrows).Process step (7) shows the discharge of the oxidized liquid fertilizer.Where urine separation toilets are used, process steps (1) to (6) showthe faecal water cycle. Process step (1 a) shows the urine dischargefrom the separation toilet. Process step (1 b) is dispensed with in thiscase.

Process steps (1 a), (8) and (8 a) show the process using urineseparation toilets with reductive nutrient production. The thin solidarrows show the solids streams (sludges, etc). Process steps (2 a), (2b), (3 a), (7 a) and (7 b) lead to (3 c) and show the solids dischargefrom the black water module into the bio waste stream. However, thesolids sources can be added in all conceivable combinations beforefragmentation, and/or before hydrolysis and/or before methanefermentation.

(1) shows the combination of faecal and urinal waste water. The sphereof application of the process proposed herein is not restricted toparticular toilets and urinals, but encompasses all types of water-flushtoilets and urinals. Urinal waste water can also be separatelydischarged and treated, as will be explained furtheron on the basis ofprocess step (8).

 Where necessary, one or more mechanical, physical and/or chemicalpresettling processes which may also produce fermentable sludges, may becarried out first (2 b). The pretreatment processes should, however, beas gentle as possible in order to improve and/or not to destroy thecoarse solids structure of the black water. Residues are separated (2 a)and can be further processed.

(2) In this process step, the possibly pretreated black water isdirected to suitable solids/liquid separation. In the case that forinstance no nutrients are to be recovered from the black water cycle,the nitrate may be used for denitrification. In this case, solids/liquidseparation can particularly preferably be carried out by anaerobicflotation.

 In this case, flotation, sedimentation and/or filtration processes arepreferably used for solids/liquid separation.

 The separable carbon in the sludge of the black water (it can be addedin the bio gas production; (3 a) & (3 c)) is thus separated from thebulk of nitrogen of urine in the liquid phase, which is important forthe operational stability of the bio gas plant.

(3) The black water from process step (2) is now subjected to oxidationby microorganisms and/or to carbon removal. The aerobic treatment step(oxidation by microorganisms and/or carbon removal) can also beinitiated with all combinations or any combustion of waste water partialstreams. Thus, the residual carbon which is dissolved in the black waterescapes as CO₂ gas. The oxidation by microorganisms also comprisesnitrification (urea is oxidized to nitrate). Here, the liquid phase fromthe bio gas plant from process step (VII) can be supplied and oxidized.

 Preferably, an activated material process is used here, which workswith a high amount of dry substance (about 15 kg_(oTS)/m³) of active biomass in order to keep the reactor volume small. However, in this casethe later solids/liquid separation process (4) has to meet specialrequirements. The oxidation by microorganisms and/or the removal ofcarbon and nitrogen can be carried out in one or two steps, and in thecase of two steps can also comprise several steps, with all combinationsof fixed bed process and activated material processes being possiblehere.

The solids/liquid separation of process step (2) and the oxidation bymicroorganisms (3) can preferably be carried out in the same apparatus.

 Nitrification proceeds smoothly and optimally only within a very smallpH window between pH 6 and 7. In the acidic range, the nitrifyingbacteria are inhibited by HNO₂-N, and in the basic range they areinhibited by NH₃-N. The nitrification process is accompanied by alowering of the pH in the medium. Due to the supply amounts depending onthe toilets used (vacuum toilets: 7-10 l/(PE*d), flush toilet: 30-60l/(PE*d) and the oxidation reactor sizes depending on the solids/liquidseparation process used in process step (4) (for instancemicrofiltration: reactor size about 27 to 33 l/PE with a reactor volumeof 20 kg_(oTS)/m³, sharp rises in activity, against whichcounter-measures might be provided, may occur. Preferably, they arebuffered in a self-regulatory manner by buffer substances buried in thereactor and provided with correspondingly reactive surfaces.

 Preferably a suitable amount of nitrified black water and/or urinalwaste water and/or faecal waster water is supplied via (3 b) and/or (5a) to the preceding solids/liquid separation process in order toaccelerate anaerobic denitrification. In this way, the solids aretransported to the surface by the gas bubbles (N₂) that form and can beremoved. The denitrifying bacteria can also be added via (III) and/or (5a). In the case that the solids/liquid separation process is carried outin the same apparatus, the separated bio mass or necessary partialamount can also remain in the apparatus.

 Preferably, the process proceeds as follows:

a) solids/liquid separation (process step (2) & denitrification,

b) oxidation by microorganisms (process step (3)), and

c) solids/liquid separation (process step (4))

 Operation is sequenced in batches (in a manner similar as in SBR) intwo alternately charged reactors preferably equipped with buffercontainers. In the case of a high load oxidation reactor (process step(3), second paragraph) it can be charged in batches and floated withsubsequent anaerobiosis.

 Preferably, all three process steps are carried out in the sameapparatus.

 In the temperature range of below about 28° C., the metabolic kineticsof Nitrosomonas (NH₄ ⁺≧NO₂) are slower than those of Nitrobacter (NO₂⁻≧NO₃ ⁻). Thus, the NO₂ ⁻ formed in the oxidation reactor is quicklymetabolized and the formation of toxic HNO₂-N is prevented. However, inthe higher temperature range the metabolic rate of Nitrosomonas isfaster than that of Nitrobacter. Thus, HNO₂-N can accumulate in thereactor and inhibit the nitrification process. As the target groups ofthe process herein proposed include hotel buildings in hot and sunnyareas, and since the very reactor is heated up by the oxidation heatreleased, it might be necessary to take suitable counter measures (forinstance to design the process as a multi-step process, use cooledaeration air, increase the concentration of the activated bio mass, oradapt the bacteria population slowly).

(4) The liquid product from (3) is now subjected to furthersolids/liquid separation. It can be carried out simultaneously inprocess step (3) by means of suitable filtration processes, in order toincrease the bio mass in (3) independently from the sedimentation limit.In this connection the following requirements must be met:

the active bio mass of the activated sludge should be held back,

pathogenic bacteria and microorganisms should be held back,

and humic acids that form and other macromolecules should be held back.

 However, all other solids/liquid separation processes (for instancesedimentation) can be used as well, which, however, influence the wholecourse of the process. For instance, after process step (4) and beforeoptional process step (5), one or more mechanical, physical, chemicaland/or oxidatively biological process step can be inserted.

 Excess sludge (7 a) can be supplied to the bio gas plant via (3 c)either together with or separately from the raw sludge of the blackwater.

 A characteristic feature of the process is the activated sludge tank (7b) which allows the necessary concentration of active bio mass in theoxidation apparatus to be appropriately adjusted depending on the dayprofile of the amounts and loads of the accruing black water inconjunction with an oxygen supply adjusted to the demand (7 c), in orderto ensure a constant drainage quality. This leads to a substantiallysmaller dimensioning of the reaction volumina and a more stable courseof the process compared to that of the prior art. The process can becomputer-controlled and/or an be DFU-(remote datatransmission)-controlled. Operation can be monitored by sensors.

 The demand-dependent and controllable bio mass concentration in theoxidation apparatus could have an influence on the special requirementsof the process of the invention. For instance, the sharp rises inacidity and/or the accumulation of HNO₂-N in the oxidation apparatuscould be counteracted by an appropriate supply of active bio mass and/orNitrobacter-enriched bio mass from the activated sludge tank. This alsoenables the plant when adequately controlled to adapt to the day profileof loads even in the case of the smallest reactor dimension.

 It is possible to take measures to prevent autolytic digestion of thebiomass in the activated sludge tank (for instance cooling). Excessactive bio mass of tank (7 d) is directed to the bio gas plant.

(5) The liquid product from process step (4) can undergo an optionalsanitation process. However, the choice of the suitable filtrationprocess (4) can render it unnecessary.

 After process step (5), another sanitation process step can be providedfor. However, chlorination of the liquid product of (5) should bedispensed with, if possible, to avoid the risk of a high saltconcentration in the black water cycle, in order for the mineralfertilizer that forms to remain pedologically safe.

(6) The product of (5) is a clear concentrated mineral fertilizersolution which can be reused via a tank to flush toilets and/or urinal.The open black water cycle is thus closed. In this way, the toilet waterconsumption of about 50 l/(PE*d) can be reduced to 0 l/(PE*d) as amaximum. The volume entering the black water cycle is about 1.5 to 2.2l/(PE*d) from human excrements. The volume of liquid fertilizer exitingthe cycle is calculated as entry volume minus sludge deductions andevaporization losses. If these deductions equal the entry volume orexceed it, it is necessary to add water to the cycle. Otherwise, theadded amount of outside water is determined by the water consumption ofthe toilets and urinals and the biologically compatible nitrogenconcentrations in the oxidation reactor.

(7) A final product of highly concentrated odorless liquid mineralfertilizer is formed which can be stored and/or used for fertilizing.The carbon portion in the mineral fertilizer solution is so low thathardly any denitrification processes occur.

 The small volume allows drying and the subsequent further processingand/packaging of the mineral fertilizer can be part of the process. Inthe case that the liquid nutrient solution is stored, care should betaken to ensure darkness and absence of air, as otherwisephotoautotrophic and/or chemoautotrophic organisms might grow, whichmight cause noticeable nitrogen looses by the supply of carbon andsubsequent denitrification.

(8) The general rule is that a combination of oxidized and nitrifiednitrogen-containing waste water and carbon-rich fermentation brothimmediately leads to great denitrification processes and thus to greatnitrogen losses.

 As shown, the nitrogen can be separated by the solids/liquid separationprocess (2) before fermentation of the carbon.

 Process step (8) now shows the process using urine separation toilets.Under these conditions too, the separately collected faecal waste watershould be subjected to solids/liquid separation, in order for the volumeof the bio gas plant to be kept small. If the liquid supernatant is tobe oxidized, so as to close the black water cycle and to oxidize NH₄-Nto NO₃-N, because odorous nitrogen stripping is thus prevented, it ispossible to reunite the urinal waste water with the faceal watersupernatants, as the same applies to the urinal waste water. Hence, theuse of separation toilets in the case of oxidative recovery of thenutrients (mineral fertilizer (KNO₃, P₂O₅, K₂O, etc.) makes littlesense.

 The use of urine separation toilets in the present process makes onlysense, if the nutrients of the urine waste water are to be recoveredanaerobically. In that case of urine, after having been subjected tofiltration in order for pathogenic microorganisms to be removed, can becombined with the digested fermentation broth from the bio gas plant (8a), without this leading to denitrification processes.

 After filtration, the pure urinal waste water can be directedseparately to drying and/or utilization (recovery) and/or furtherprocessing (8 a). Its concentration by reverse osmosis is also useful.

 Also, the proper use of MAP precipitation (magnesium ammoniumphosphate), or other precipitation processes in the urinal waste wateroptionally after sanitation would be conceivable. In a precipitationprocess in the acidic medium it would be useful to subject the urinalwaste water prior to reuniting it to anaerobic hydrolysis for thepurpose of acidification so as to change the NH₃−NH₄ ⁺ solubilitybalance in the urinal waste water in favour of the NH₄ ⁻ concentration.

 Adsorptive processes for ammonium (such as clay minerals, zeolite,etc.) can also be useful and thus form part of the process. Moreover,combinations of precipitation, adsorption and/or drying are possible.

 Furthermore, sterilization or sanitation steps before, after or insteadof filtration would be conceivable.

 The solids/liquid separation of faecal waste water continues to beuseful, so as to keep the volume of the bio gas plant small. In thiscase, the oxidation of faecal waste water from process step (3) can beperformed with a substantially lower energy consumption because of theabsence of about 88% of the nitrogen, than in combination with theurinal waste water, and this would result in a substantial reduction ofthe operation costs of the oxidation apparatus in the black water cycle.The reactor size of the oxidation apparatus would also be distinctlysmaller. The reductive nutrient recovery of the urinal waste water is agood supplement of the oxidative nutrient recovery from faecal wastewater and avoids the problems of the above-described process steps (3)and (4). However, nitrogen losses due to escaping NH₃ gas must beexpected.

The bio waste stream

In the following, the bio waste stream and its interaction with the grayand black water cycles are described. In summary, this partial stream ofthe process aims at a high bio gas yield and high sanitation of theorganic material.

(I) In hotels, bio waste of is generated only in a few places, and canthus often be separated without having to be sorted out. Bio waste isgenerated primarily in

large kitchens

restaurants

gardens and parks

 Once the personnel has received corresponding instruction, a highdegree of homogeneity of the kinds is easy to achieve. In this respect,the separation is provided as an optional process step. However, theseparation of the residual material by gravity separation or othermethods can also be provided as an additional process step at adifferent stage in the bio waste stream (for instance (III)). Theresidual or interfering materials are separated and can be furtherprocessed.

(II) The bio waste which should be as homogeneous as possible regardingkinds is now subjected to fragmentation. Fragmentation can be carriedout with or without the sludges from the black water stream ((2 b), (3a), (7 d) and/or (7 a)). Preferably, bio waste fragmentation is carriedout without the sludges by means of a “cutter”, as used in largebutcheries for sausage production. Cutters perform very goodfragmentation and homogenization of the bio waste.

(III) The sludges separated from process steps (3 a) and (7 a) are forinstance mixed with the fragmented bio waste and subjected tohydrolysis. If the total black water, instead of the black watersediment from (3 a), were used with the bio waste for fermentation (orurinal waste water separation, and (3) being added to (3 a) and (3 c)),the high nitrogen concentrations could endanger the methanation processin the bio gas plant. Sedimentation of the black water for separatingthe nitrogen (urea) prior to fermentation is thus recommendable from aprocess technological point to view without the use of urine separationtoilets. Moreover, sedimentation permits a reduction of the requiredsize of the bio gas plant.

 If urine separation toilets are used, the total faecal waste water canbe directed into the bio gas plant ((3) via (3 a) and (3 c)), withoutthere being any danger that the methanation process is inhibited, asmore than 80% of the nitrogen are dissolved in the urine. This wouldresult in the sanitation of the faecal waste water and an increase inthe bio gas yield, but also in a substantially greater dimension of thebio gas plant.

 Hydrolysis is preferably thermophilic with a suitable retention time,in order to achieve the simultaneous sanitation of the organic material.

(IV) In this process step, the hydrolyzed material is preferablysubjected to mesophilic methane fermentation. Methane fermentation isthe interface to the gray water module. The material separated from thekitchen waste waters by fat separators or flotation processes isdirectly charged into the methane fermentator, as the hydrolysis of fatsis the rate-limiting step in the anaerobic catabolism of fats.

(V) The digested fermentation broth can now be subjected to an optionalsolids/liquid separation process. The liquid supernatant contains manynutrients and can be directed to oxidation (3) (VII), or, preferablyprior to filtration, to the reductive process line of the urinal wastewater (VIIb).

(VI) The digested product from (V) or (VI) can now be directlyrecovered, dried, or further processed. In the case of composting, thewater or irrigating the compost can be drawn from the gray water, orfrom treated faecal and/or urinal waste water. It is then collected andcan be subjected to oxidation via process step (VIIIa) or directed tothe reductive urinal waste water stream.

(VII) The supply of liquid from (VII) and/or (VIIa) allows liquid lossesof the black water cycle to be compensated for. The compost water cycleis described in FIG. 3.

FIG. 2: The Gray Water Stream

Introductory Description of the Process

This partial stream of the process aims at the production of highlypurified water for domestic use. The final goal may be the production ofpotable water from gray water or from partial streams of gray water.This goal can be attained by membrane filtration using reverse osmosisand/or micro- and/or ultrafiltration with subsequent salt removal.Regarding the membranes it is necessary to ensure that they have thesuitable pore size; for instance for residual COD (chemical oxygendemand) solids retention, sanitation etc. After optional sedimentation,the carbon in the gray water is first removed by wet oxidation (possiblywith the addition of black water nutrients) or by other biological,chemical or physical processes. Nitrogen and phosphorus need not beremoved, but their removal may be brought about by other processes (forinstance precipitation of the carbon) or may be provided for as (a)separate, biological, chemical or physical process step(s).

The activated sludge generated in biological carbon degradation is fixed(fixed bed process) or is recycled (activated sludge process). Excesssludge or precipitated sludge is separated by conventional solids/liquidseparation processes, and can, for instance, be directed to a bio gasplant.

The scarcely degradable CSB fraction remaining in the liquid phase canbe oxidized to CO₂ by ozonization or other processes, and/or can beremoved by other biological, chemical or physical processes. Afteroptional further solids/liquid separation (for instance filtration), thesubstances remaining in the gray water are subsequently removed byactivated charcoal filtration or by other processes (for instancefiltration or adsorption processes). As gray water contains relativelyfew salts, salt removal (for instance reverse osmosis) is not evisagede.g. in the case of a permanent admixture of salt-low potable water inareas with heavy rain falls, but can be a process step. In areas withextreme water shortage, the oxidized gray water can be processed toprovide water in the often already existing sea-water desalinizationplants in a multifunctional manner; simultaneous retention of salts,pathogenic microorganisms, and nutrients possibly still present andresidual CSB can be achieved.

After sanitation and optional chlorination it is directed to the potablewater tank. Sanitation and chlorination are optional process measures.

A process step to modify or neutralize the water structure can beinserted here at a suitable stage (for instance after activated charcoaladsorption). The process can comprise a ground water passage in order tocomply with legal requirements but this passage is not necessary fromthe point of view of process technology.

Description of the Process on the Basis of FIG. 2

The dashed boxed or lines and arrows in FIG. 2 also represent optionsand variants of the process.

(1) Usual mechanical and/or physical and/or chemical pretreatmentprocesses of gray water or one or more of its partial streams (forinstance rake separators, sand separators and separators of light weightmaterials etc.) can be carried out first. In this case, a division ofthe gray water into gray water partial streams according to theirorigins and pollution characteristics seems to be more expedient.

(2) The kitchen wastes contain fats, oils, floating and sedimentablesolids and tensides and dissolved, organic substances. The pretreatmentrecommended here is a flotation process by which the fats, oils, thefloating and sedimentable solids, and some of the dissolved BOD(biological oxygen demand) solids and COD (chemical oxygen demand)solids are withdrawn and can be directed into the methane fermentator ofthe black water and bio waste module. It is also possible to use fatseparators, filtration, precipitation and other separation processeshere.

(3) It would be worth considering separately collecting the waste waterfrom the kitchen operation (2) and the kitchen waste waters (3) andsubsequently performing coarse/fine screening because of the particularpollution characteristics. Also, a separation of the kitchen cleaningwaste waters (3) from the gray water stream and/or separate purificationbecause of the aggressive cleansing substances is possible.

(4) Hair and other fibre-like substances are found apart from tensidesand the like in the gray water sources, such as showers, wash basins,bath tubs and washing machines. Moreover, nitrogen admixture of humanorigin must be taken into account here. Hence, the joint collection andpretreatment with a coarse screen and fine screen process of the graywater sources is recommended here (“Washing”).

(5) The section “pool and/or remainder” consists of the recycle sludgesfrom the pool water purification plant, the very pool water which is tobe exchanged, and other gray water sources, mostly in the outdoor area.The human user leaves body oils, nitrogen and other nutrients there aswell as salts which are perspired through the skin but are alsointroduced by the chlorination of the pool water. Because of itspermanent chlorination, pool water involves no danger of epidemics, andtherefore this gray water can be used without further processing towater close by green areas and can be applied there as a fertilizerwithout any danger of overdosing, (compared to black water its N-loadsare low).

(6) The low nutrient content of the gray water stream “pool” and/or“remainder” would, however, also be suitable in the subsequent oxidationstep (oxidation by microorganisms and/or carbon removal) of the othergray water streams, and therefore fine screening and/or filtration andsubsequent direction towards oxidation would be expedient.

(7) The pretreated gray water streams are reunited prior to oxidation(oxidation by microorganisms and/or carbon removal) and are subjected toa suitable oxidation process using microorganisms (aerated sand filter,planted soil filter, vertical intermittently charged soil filterswithout plants, etc.). In the case of nutrient shortage, a mineralfertilizer solution from the black water cycle may be added here. Afterprocess step (7) and before process step (8), one or more mechanical,physical, chemical and/or biological purification steps may be inserted.

(8) The liquid product form (7) is now purified by a desalinizationplant. In this manner, the following objects can be achieved at the sametime:

retention of the salts

retention of the residual bio mass

retention of the CSB residue

sanitation

 As in many touristic areas potable water is obtained from sea-waterdesalinization plants, the purified gray water can be mixed togetherwith sea water or can be separately and centrally processed to potablewater in a desalinization plant at favourable conditions because of thelow osmotic pressure. The salty residue of the desalinization plant isdirected into the sea (14).

(9) The product from (8) can now be subjected to sanitation (processsteps (12) and (13)) or optionally subjected to a process for changingthe water structure.

(10) The purified gray water can be chlorinated as an additional safetymeasure prior to its reuse and/or storage (11).

FIG. 3: Flow Diagram of the Black Water Components

FIG. 3 shows the black water sedimentation and the oxidative nutrientwithdrawal from the bio waste stream as a flow diagram. C, N, P, K standfor the reduced organic compounds of these elements, CO₂, KNO₃ and PO₄stand for the oxidized ones. CH₄ stands for the withdrawal of carbon asenergy carrier (bio gas).

Carbon: A Valuable Energy Carrier

Carbon must be removed from the waste water. This is done in two ways:First, by sedimentation (1) (sludge is heavier than water) and secondlyby subjecting the residual solute carbon to biological “burning” (2) bybacteria. Hence, the bulk of the carbon is now present as a sludge andgarbage ((1) & (2)). One possibility is to compost them (6) which isalso a biological burning of the biologically easily degradable carboncompounds. This release much energy. Everyone knows the steaming compostheaps in rural areas. However, this waste heat from composting canhardly be used. Another possibility is the fermentation of easilydegradable carbon compounds under air seal (4). As oxygen is no longerpresent, bio gas (CH₄) is now formed instead of CO₂. This energy carriercan be used in many ways.

As not all carbon compounds can be degraded under air seal, the digestedorganic material can subsequently be composted (6) and in this manner acompost whose quality is even superior to that of the previous one isobtained.

N, P & K: Elixir of Life for Areas Under Cultivation

Plants assimilate nitrogen in two forms via their roots: As nitrate NO₃,or as ammonium NH₄, phosphorus is assimilated as phosphate PO₄ andpotassium as potassium ion K⁺. As a result of the biological “burning”of the carbon in the waste water (2), not only CO₂, but also highamounts of potassium, nitrate and phosphate are released, which,however, remain dissolved in the water.

These so-called problematic substances which must be removed at greatexpense if the purified waste water is directed into rivers or lakes,are highly welcome fertilizers in the case of areas under cultivation ifthe purified waste water is used for the irrigation of the areas undercultivation. Commercial mineral fertilizer consists of salpeter KNO₃,that is to say potassium nitrate and phosphate PO₄. Exactly thesesubstances are produced by the process and can be applied to the areaunder cultivation in solute form.

In the irrigation (FIG. 3: (7), FIG. 1: (VIIc)) of the composting step(FIG. 3: (6), FIG. 1: (VI)), not only potassium, nitrate and phosphatebut also carbon substances are washed out; they are removed by directingthe “compost water” again to the aerobic treatment step (oxidation bymicroorganisms and/or carbon removal) (FIG. 3: (2), FIG. 1: (VIIa)). Inthis manner, the organically bound nitrogen present in the irrigationwater of the composting step (FIG. 3: (6), FIG. 1: (VI)) and/or presentin the drainage water from the drainage step (FIG. 3: (5), FIG. 1: (V))of the bio gas plant is oxidized to nitrate, and thus leads to a highnutrient-enrichment in the effluent of the waste water treatment plantvia the circulation system of the water.

In this manner, a maximum concentration of plant nutrients in the clearand pure irrigation water is achieved.

FIG. 4 and FIG. 5: Black Water Nodule and Bio Waste Module withMultifunctional Solids/Liquid Separation

FIG. 4 shows the use of the process as a compact module which can beplaced into basements. In non-vegetation periods (winter) and productionof mineral fertilizer may be undesirable.

Another feature of the process is the dentrification step, which can beadded or omitted, and the biological phosphate removal, as theapplication of nutrients on green areas is not desirable in the winter.

The process is now explained in more detail on the basis of FIGS. 4 and5: The raw waste water or preferably black water is directed via conduit(1) into a chamber filter press. This chamber filter press can bereplaced with other conventional solids/liquid separation processes. Thesolids-containing filtrate can be adjusted with the solids/liquidseparator to a desired dry substance content, which is desirable toreduce the volume of the reduction apparatus.

The solids-containing filtrate is directed via conduit (2) eitherseparately or together with the bio waste (3) into a reduction apparatusfor anaerobic conditioning and production of bio gas.

After digestion of the organic material, the fermentation broth is againdirected into the solids/liquid separator via the conduit (FIG. 4: (10),FIG. 5 (11)). The filter cake thereby formed (FIG. 4: (11), FIG. 5:(12)) can be disposed of in a garbage bin, applied in the garden orprocessed further.

A. Nutrient Utilization

The liquid filtrates from (FIG. 4: (11), FIG. 5: (12)) and (1) aredirected to the oxidation apparatus (oxidation by microorganisms and/orcarbon removal) via conduit (4), if nutrient processing and recovery orstorage is desired. In the oxidation (oxidation by microorganism and/orcarbon removal) the carbon compounds are oxidized to CO₂ and thenutrients are mineralized to KNO₃, K₂O, PO₄, etc. After completeoxidation, the active bio mass thereby formed is directed via conduit(5) to the solids/liquid separator and pressed. Here, too, the desireddry substance contents can be adjusted. The solids-free, mineralizedblack water is reused for toilet flushing via conduit (9) (FIG. 5).Thus, the black water is directed in an open cycle, in which thenutrients are concentrated.

The present bio mass is directed to an activated sludge tank via conduit(6). Measures to prevent the autolytic digestion of the bio mass can betaken in the activated sludge tank. If the demand of active biomass inthe oxidation apparatus is high, (in the case of high throughputtedamounts and/or of a high degree of pollution) the concentrated activebio mass is directed to the oxidation apparatus and the oxygen supply isincreased accordingly, and the degradation speed is thus increased.Excess active bio mass is directed to the reduction apparatus viaconduit (8).

B. No Nutrient Utilization

If nutrient utilization is not desired, the oxidized nitrogen (NO₃),following complete oxidation, is denitrified by conventional processesfor instance in the oxidation apparatus, and phosphorus is biologicallyfixed or removed otherwise. This is preferably done in the oxidationapparatus, which becomes the reduction apparatus by switching offaeration and stirring. In this process, carbon can be provided viaconduit (4) and admixed. In a particularly preferred embodiment,denitrification by the high nitrate concentrations available from theblack water cycle can be used for flotation in the first solids/liquidseparation of the black water and/or faecal waste water. As a highconcentration of facultatively anaerobic bacteria is found in theactivated sludge tank, denitrification can be increased very efficientlyby the addition of active bio mass also via conduit (7).

If necessary, intermittent aeration can be applied and/or additionalsolids/liquid separation steps can be carried out within the degradationprocess. Excess active bio mass is directed to the reduction apparatusvia conduit (8).

What is claimed is:
 1. A process for utilizing waste waters; the processcomprising: (a) separately collecting gray water, or one or more partialstreams thereof, and black water, or faecal discharges and urinaldischarges; (b) selectively performing solids/liquid separation of thegray water and the black water or the faecal discharges and urinaldischarges separately collected in (a); (c) selectively performingoxidation by microorganisms of the liquid phases of the gray water andthe black water or the faecal discharges and urinal discharges obtainedin (b); and (d) selectively performing solids/liquid separation of atleast one of the liquid phases obtained in (c).
 2. The process accordingto claim 1, further comprising: after (c) or (d), creating a mixture byselectively mixing the gray water, or the one or more partial streamsthereof, with sea water; and subsequently desalting the mixture in adesalinization plant.
 3. The process according to claim 1, furthercomprising selectively subjecting solids from the gray water and theblack water or the faecal discharges and fragmented bio waste to one ortwo-step anaerobic digestion.
 4. A process for utilizing waste waters;the process comprising: (a) separately collecting gray water and blackwater, wherein the black water is collected from toilets with or withouturinals; (b) performing membrane filtration of the gray water separatelycollected in (a), and (ba) separately performing solids/liquidseparation of the black water separately collected in (a); (c)performing oxidation by microorganisms of the liquid phases obtained in(ba); (d) performing solids/liquid separation of the product obtained in(c); (e) selectively utilizing the liquid phase obtained in (d) for atleast one of (i) collecting black water according to (a); and (ii) asmineral fertilizer; and (f) optionally repeating (a) through (e) one ormore times.
 5. The process according to claim 4, wherein the separatelycollecting in (a) further comprises collecting the black waterseparately as a faecal waste water partial stream and a urinal wastewater partial stream, and wherein the faecal waste water is treatedaccording to steps (a) to (f).
 6. The process according to claim 5,further comprising adding at least a part of the urinal waste water tothe faecal waste water prior to (c).
 7. The process according to claim6, wherein the separately performing solids/liquid separation in (b)further comprises a flotation process if steps (a) to (e) are repeatedone or more times.
 8. The process according to claim 5, furthercomprising selectively performing, prior to (c), one or more mechanical,physical, and chemical purification steps.
 9. The process according toclaim 8, wherein the performing solids/liquid separation in (d)comprises performing a filtration process.
 10. The process according toclaim 5, wherein the separately performing solids/liquid separation in(b) comprises performing a sedimentation or filtration process.
 11. Theprocess according to claim 5, further comprising selectively storing theproduct of (d) in a tank, and in the case of higher performance demand,selectively re-supplying the contents of the tank to an oxidationapparatus performing (c) under increased air supply.
 12. The processaccording to claim 5, further comprising selectively subjecting theoxidized black water or the faecal waste water to sanitation andmodification of the water structure prior to reutilization.
 13. Theprocess according to claim 5, further comprising selectively removingsolids from the urinal waste water partial stream by filtration.
 14. Theprocess according to claim 4, further comprising depositing the mineralfertilizer into containers.
 15. The process according to claim 4,wherein steps (b), (c), and (d) are carried out in an apparatuscomprising a reactor; the reactor comprising membranes for solids/liquidseparation and apparatuses for aerating, stirring, measuring, andadjusting the pH value of the contents of the reactor; and wherein theapparatus is hydraulically connected to a storage container to which andfrom which active bio mass of the reactor can be supplied.
 16. A processfor producing potable water from gray water or from one or more partialstreams thereof, the process comprising: (a) separately collecting graywater or one or more partial streams thereof and creating a mixture byselectively mixing the gray water, or the one or more partial streamsthereof, with sea water; (b) selectively performing membrane filtrationof the mixture; wherein the membrane filtration is carried out by one ofreverse osmosis, ultrafiltration, or microfiltration; and (c)selectively performing desalinization of the mixture where the membranefiltration in (b) is carried out by ultrafiltration or microfiltration.17. The process according to claim 16, wherein the selectivelyperforming membrane filtration comprises utilizing membranes having apore size of at the most up to 2 μm.
 18. The process according to claim17, wherein the selectively performing membrane filtration comprisesutilizing membranes having a pore size of at the most 0.2 μm.
 19. Theprocess according to any one of claims 4, 16, 17 or 18, furthercomprising selectively performing, prior to (b), one or more mechanical,physical, and chemical purification steps.
 20. The process according toclaim 19, further comprising selectively performing, subsequent to (a):(i) solids/liquid separation; and (ii) carbon removal.
 21. The processaccording to claim 20, further comprising selectively performingsolids/liquid separation subsequent to (ii).
 22. The process accordingto claim 20, wherein the solids/liquid separation in (i) comprisesselectively performing one of flotation, sedimentation, filtration, orprecipitation.
 23. The process according to claim 19, wherein theselectively performing one or more purification steps comprisesperforming a process of carbon removal carried out by oxidation bymicroorganisms.
 24. The process according to claim 16, furthercomprising depositing the potable water into containers.
 25. The processaccording to claim 16, wherein steps (b) and (c) are carried out in anapparatus; the apparatus comprising a separator in which the processsteps are carried out, and wherein the apparatus further comprisesequipment for carrying out the desalinization.
 26. The process accordingto claims 4 or 16, further comprising selectively performing sanitationand modification of the water structure of the gray water or one or morepartial streams thereof recovered in (b).
 27. The process according toclaim 26, wherein the selectively performing sanitation comprisesperforming a chlorination treatment.